Hassan W. Nemeh

Gastrointestinal bleeding with the HeartMate II left ventricular assist device.

BACKGROUND Continuous flow left ventricular assist devices (CF-LVADs) have yielded improved outcomes compared with pulsatile flow devices for patients on long-term support. However, significant rates of gastrointestinal bleeding (GIB) have been observed during CF-LVAD support. METHODS From March 2006 through March 2011, 86 patients with chronic heart failure underwent implantation of a CF-LVAD (HeartMate II; Thoratec Corp., Pleasanton, CA). Records were reviewed to determine the prevalence of post-implant GIB, location of the bleeding site and associated morbidity and mortality. Uni- and multivariate analyses were conducted to identify independent predictors of GIB. RESULTS GIB occurred in 19 patients (22.1%) with a duration of support that ranged from 5 to 456 days. Sources of GIB included small bowel and rectum in 6 patients each, large bowel in 2 patients and stomach in 1 patient. No definite source was identified in 4 patients. There were no deaths referable to GIB. Recurrent GIB occurred in 4 patients. History of a GIB prior to LVAD implant was the only variable significantly different between patients with and without post-implant GIB (21.1% vs 10.4%, p = 0.016), and was the only independent predictor of GIB (OR = 2.24, 95% CI 2.121 to 2.435, p = 0.004). CONCLUSIONS Gastrointestinal bleeding is a frequent source of morbidity for patients on HeartMate II LVAD support but does not significantly impact survival. As implantation of CF-LVADs with non-pulsatile flow gains popularity for both bridge-to-transplant and destination therapy, a better understanding of the pathophysiology of GIB in these patients will be needed for minimizing this complication.

Impact of continuous-flow left ventricular assist device support on right ventricular function

BACKGROUND Continuous-flow (CF) pumps have yielded improvements in short- and long-term survival and quality of life, and have reduced the number of left ventricular assist device (LVAD)-related complications. However, their ability to unload the right ventricle (RV) and improve RV function has not been as clearly defined. We evaluated the short- and mid-term effects of CF-LVADs on central venous pressure (CVP), pulmonary artery pressures (PAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), RV ejection fraction (RVEF), RV end-diastolic dimension (RVEDD), RV stroke work index (RVSWI), tricuspid annular plane systolic excursion (TAPSE) and severity of tricuspid regurgitation (TR). METHODS From March 2006 through June 2012, 130 patients with chronic heart failure underwent implantation of a CF-LVAD (122 HeartMate II and 8 HeartWare devices) as a bridge to transplant (n = 76) or as destination therapy (n = 54). Patients with pre-operative long-term LVADs (n = 4) and patients who underwent concomitant tricuspid valve repairs during their LVAD implant (n = 21) were excluded from the analysis. Echocardiograms and right heart catheterizations of the remaining 105 patients were reviewed pre-operatively and at 1 and 6 months post-LVAD implantation. RESULTS At 1 month post-LVAD implantation, CVP decreased from 12.4 ± 5.9 mm Hg to 8.7 ± 4.5 mm Hg (p < 0.001), systolic PAP decreased from 52.3 ± 14.1 mm Hg to 36.8 ± 11.3 mm Hg (p < 0.001), PCWP decreased from 23.0 ± 9.4 mm Hg to 12.9 ± 8.0 mm Hg (p < 0.001), CI index increased from 1.8 ± 0.5 liters/min m2 to 2.4 ± 0.5 liters/min m2 (p < 0.001), RVEF increased from 33.1 ± 4.9% to 40.4 ± 6.2% (p < 0.001), RVEDD decreased from 36 mm to 31 mm (p = 0.020), RVSWI improved from 408.6 ± 144.6 mm Hg ml m2 to 614.4 ± 196.2 mm Hg ml m2 (p < 0.001), and mean TAPSE increased from 1.1 ± 0.4 cm to 1.9 ± 0.4 cm (p = 0.004). Similarly, qualitative RV function on echocardiography improved from 57.1% moderately or severely reduced pre-operatively to 38.1% at 1 month (p = 0.008). Severity of TR decreased from 11.4% moderate or severe pre-operatively to 4.8% at 1 month (p < 0.001). These improvements were maintained at 6 months post-LVAD. CONCLUSIONS CF-LVAD support significantly decreased CVP and RVEDD, with concomitant improvement in RV function, as measured by increases in RVEF, RVSWI and TAPSE, as well as improvements in the qualitative echocardiographic appearance of RV contractility and a reduction in TR.

LVAD destination therapy: applying what we know about psychiatric evaluation and management from cardiac failure and transplant

Left ventricular assist devices (LVADs) have evolved into long-term use as destination therapy for those with severe end-stage heart failure due to other medical risks. Success with LVAD depends on adherence to a complicated mechanical regimen, and acceptance of a life that is far from normal. Patients with LVADs share characteristics with other end-stage cardiac failure patients and those waiting for or receiving heart transplants. Understanding the more thoroughly studied issues of psychiatric disorders, adherence, and behavioral correlates of success in heart failure and transplantation may identify feasible strategies for optimizing care of LVAD patients and suggest directions for future research. Depression and distress complicate post-transplant care. Psychiatric morbidity is associated with poor outcomes, including graft rejection, non-adherence, hospitalizations, infection, and death. With a high risk of embolic neurological events, patients’ ability for self-care may be compromised. Psychiatric symptoms are underdiagnosed and undertreated, which may impact overall survival and quality of life.

Non-cardiac surgery in patients on long-term left ventricular assist device support

BACKGROUND An increasing number of patients on left ventricular assist device (LVAD) support are requiring non-cardiac surgical (NCS) procedures. We reviewed our experience with the management of patients on continuous flow (CF) LVAD support undergoing NCS. METHODS From March 2006 through March 2011, 86 patients with chronic heart failure underwent implantation of a HeartMate II (Thoratec Corp, Pleasanton, CA) LVAD. Clinical records of these patients were reviewed to identify patients who underwent NCS while on LVAD support, with a focus on peri-operative death, bleeding, thrombosis, and device malfunction, as well as management of pre-operative anti-coagulation. RESULTS While on CF-LVAD support, 20 patients underwent 25 NCSs, comprising 13 major and 12 minor procedures. Operations were performed electively in 22 and as emergencies in 3. No peri-operative deaths, thromboembolic complications, or device malfunctions occurred. The incidence of bleeding requiring transfusion of packed red blood cells was 36.0%, including 25% of patients undergoing minor NCSs and 46.2% undergoing major NCSs (p = 0.004). All bleeding complications occurred in patients on both warfarin and aspirin pre-operatively. The only significant differences between patients who did and did not require transfusion were pre-operative warfarin use and significantly higher pre-operative international normalized ratio in the transfused group (1.9 ± 0.4 vs 1.4 ± 0.3; p = 0.008). CONCLUSIONS Non-cardiac operations can be performed safely in patients with CF-LVADs. It may possible to reduce peri-operative bleeding by lowering pre-operative anti-coagulation goals, especially before major surgery. However, additional analysis is required to determine if this can be performed safely.

Stroke while on long-term left ventricular assist device support: incidence, outcome, and predictors.

Development of stroke while on left ventricular assist device (LVAD) support can be a source of significant morbidity and mortality. From March 2006 through November 2011, one hundred patients with chronic heart failure underwent implantation of a HeartMate II (HM II) LVAD (Thoratec Corp.) as a bridge to transplant (BTT; n = 65) or destination therapy (DT; n = 35). Records were reviewed to determine the prevalence and type of postimplant stroke, anatomic cerebral location of strokes, and associated morbidity and mortality. Cox multivariate logistic regression analysis was conducted to identify independent predictors of postoperative stroke. Strokes occurred in 12 patients (12.0%): four embolic and eight hemorrhagic. Median duration of support at the time of stroke was 281.0 days for embolic strokes and 380.5 days for hemorrhagic strokes (p = 0.028). Stroke patients had a significantly higher incidence of diabetes (66.7% vs. 40.9%; p = 0.024), history of preimplant stroke (16.7% vs. 4.5%; p = 0.046), and aortic cross-clamping with cardioplegic arrest during their LVAD implant (50.0% vs. 20.2%; p = 0.034) compared with patients without postoperative strokes. Mean international normalized ratio (INR) at the time of stroke was subtherapeutic in all four patients with embolic strokes (mean: 1.5 ± 0.1 IU; range 1.3–1.6 IU) and supratherapeutic in four of eight patients with hemorrhagic strokes (mean: 3.2 ± 2.2 IU, range: 1.4–7.0 IU; p = 0.024). There was a 25.0% 30 day mortality after stroke. Diabetes (odds ratio [OR] 6.36; p = 0.029), aortic cross-clamping with cardioplegic arrest (OR 4.75; p = 0.025), duration of LVAD support (OR 1.00; p = 0.008), and INR (OR 4.42; p = 0.020) were independent predictors of stroke in multivariate analysis with a trend toward significance for history of stroke (OR 6.25; p = 0.075). Stroke represented an important source of morbidity and mortality for patients on HM II LVAD support. As long-term device therapy continues to gain popularity for both BTT and DT, a better understanding of the predictors of stroke, more strict control of postoperative anticoagulation, and the establishment of a risk stratification model may aid in minimizing its occurrence.

Factors determining post-operative readmissions after left ventricular assist device implantation

BACKGROUND In the current era of extensive healthcare reform, there has been a heightened focus on the frequency and cause for readmissions within 30 days of discharge given that readmissions are not reimbursed by most providers. The aim of our study was to determine the frequency, etiology and patterns of 30-day readmissions among recipients of continuous-flow left ventricular assist devices (LVADs) at our institution as well to determine whether there were any significant predictors of readmission. METHODS From March 2006 through June 2013, 150 patients underwent implantation of a continuous-flow LVAD at our institution. Patients were stratified into two groups based on their 30-day readmission status. A total of 12 patients died before discharge and were excluded from our analysis. Causes for 30-day readmissions and duration of hospital stay for the readmissions were recorded. Numerous pre-operative variables and post-operative complications were compared using 2-sided t-tests and chi-square tests between patients who were and were not readmitted within 30 days of their discharge after their LVAD implant. RESULTS The 30-day readmission rate was 26.1% (36 of 138), with approximately 70% of post-operative readmissions occurring within 10 days of the patients initial hospital discharge. Recurrent heart failure (12 of 36, 33.3%) and gastrointestinal bleeding (8 of 36, 22.2%) were the most common causes for 30-day readmission. The median length of stay (LOS) for readmission was 11.7 days. Thirty-day readmission did not affect short- or long-term survival. On univariate analysis, post-operative gastrointestinal bleeding (GIB) was a significant risk factor for 30-day readmissions (HR 1.4, 95% CI 0.19 to 0.99, p = 0.05), and overall length of stay was a significant factor in reducing 30-day readmission rates (HR 0.91, 95% CI 0.85 to 0.99, p = 0.02). CONCLUSIONS Our experience indicates that 30-day readmission rates after LVAD implantation remain relatively high, with most occurring within 10 days of discharge. Recurrent heart failure and GIB were the most common causes of post-operative rehospitalization. In addition, GIB during the index hospitalization was a significant predictor of 30-day readmission.

Timing of basiliximab induction and development of acute rejection in lung transplant patients

BACKGROUND Acute rejection affects more than 36% of recipients within the first year post-transplantation. The interleukin-2 (IL-2) receptor antagonist basiliximab has been associated with decreased frequency and severity of acute rejection. We investigated whether the timing of induction administration would impact the frequency and severity of acute rejection in the first year after transplantation. METHODS In this study we reviewed 119 patients who underwent lung transplantation at Henry Ford Hospital from October 1994 to January 2009. Prior to January 2000 no patients received induction. From January 2000 to March 2006 the initial dose was given after implantation, and from March 2006 to 2009 basiliximab was given prior to implantation. The primary outcome was cumulative acute rejection score (CAR) in the first post-operative year comparing post- vs pre-implant induction. RESULTS The CAR score for pre-implant basiliximab was 2.5 ± 2.3. This was significantly lower than CAR score of 4.6 ± 3.9 in the post-implant group (p = 0.025). The no-induction group had the highest CAR score at 6.3 ± 3.8 (p = 0.077 compared with the post group). The mean follow-up times in the post and pre group were 5.9 ± 2.3 and 2.3 ± 0.7 years, respectively (p < 0.001). There was no difference in freedom from bronchiolitis obliterans syndrome (BOS), survival or invasive infections between pre- and post-implant induction groups. CONCLUSIONS Basiliximab prior to implant is associated with a lower cumulative acute rejection score over 1 year compared with induction post-implantation. Despite a lower cumulative acute rejection score, there was no significant difference in freedom from BOS or survival.

Management of Aortic Valve Insufficiency in Patients Supported By Long-Term Continuous Flow Left Ventricular Assist Devices

Continuous flow (CF) left ventricular assist devices (LVADs) have yielded improved outcomes in patient survival and quality of life compared with first-generation pulsatile pumps; however, they have been associated with an increased incidence of postimplant aortic valve insufficiency (AI), which can have can have serious clinical consequences if not diagnosed and treated expeditiously. We reviewed our experience with AI after LVAD since the start of our CF LVAD program. From March 2006 through July 2011, 94 patients with chronic heart failure underwent implantation of a HeartMate II (HM II) LVAD. Severe AI developed in three patients after CF LVAD implantation. The clinical records of these patients were reviewed to analyze the presenting signs and symptoms of AI, identify the duration of LVAD support when the AI occurred, how the AI was treated, and the outcomes.

Impact of concomitant cardiac procedures performed during implantation of long-term left ventricular assist devices

BACKGROUND There is a paucity of data evaluating the effect of performing a concomitant cardiac procedure (CCP) on peri-operative survival in patients undergoing implantation of long-term left ventricular assist devices (LVADs). The objective of this study was to review our single-institutional experience with patients who underwent a CCP during implantation of a long-term continuous-flow LVAD. METHODS From March 2006 through June 2012, 130 patients underwent implantation of a LVAD. Of these, 76 (58.5%) were implanted as bridge-to-transplant and 54 (41.5%) as destination therapy. The LVAD implantation was isolated in 95 patients and with CCP in 35. This included 19 tricuspid valve repairs, 14 aortic valve repair/replacements, and 2 patent foramen ovale closures. The LVAD only and LVAD+CCP groups were compared regarding pre-operative demographics, peri-operative and midterm survival, and the incidence of post-operative complications. RESULTS Pre-operative central venous pressure (p = 0.047), moderate to severe tricuspid regurgitation (p = 0.011), cardiopulmonary bypass time (p < 0.0001), cross-clamp time (p < 0.0001), and right ventricular end diastolic diameter (p = 0.039) were higher in the CCP group. Body mass index (p = 0.01) and body surface area (p = 0.037) were higher in the LVAD-only group. Peri-operative and midterm survival at 30 days, 6 months, 1 year, and 2 years was 94%, 87%, 80%, and 73%, respectively, for isolated LVAD implants vs. 97%, 90%, 86%, and 86%, respectively, for LVAD+CCP (p = NS). Survival was similar for LVAD patients with tricuspid valve repairs, with aortic valve repair, and with patent foramen ovale repair (p = NS). Cox proportional hazard models showed a CCP was not an independent predictor of outcome (p = NS). CONCLUSIONS CCPs performed during implantation of a long-term continuous-flow LVADs does not increase peri-operative or mid-term mortality. In addition, unlike previous reports, there was no additive procedural risk for patients undergoing concomitant aortic valve repair or replacement.

Effect of Body Mass Index on Outcomes in Left Ventricular Assist Device Recipients

Obesity is associated with higher mortality following heart transplantation, but there remains no consensus regarding outcomes in left ventricular assist device (LVAD) recipients. We sought to determine the impact of body mass index (BMI) on outcomes in patients undergoing LVAD implantation.